The invention is related to the support of a floating caliper of a spot-type disc brake on an axially external brake shoe.
In a known spot-type disc brake, a floating caliper is axially slidingly supported on a brake carrier on its axially internal side by means of pin guides received on two axial pins anchored to the brake carrier, and on its axially external side it is supported on the carrier arms of the brake carrier through a brake shoe. This external side support is necessary for insuring accurate positioning of the floating caliper, since the pin guides on the pins have an inherent play. In order to prevent any rattling of the floating caliper in its guides, the latter is clamped against the brake carrier by means of a housing spring.
A spot-type disc brake of this kind is known from the German patent application published without examination, No. 3,014,057. In this instance, the floating caliper is supported on the brake carrier radially and circumferentially through two carrier elements of the axially external brake shoe . For support in the circumferential direction, the carrier elements of the brake shoe are furnished with projections which straddle the floating caliper laterally and are positioned between the floating caliper and the carrier arms of the brake carrier in the circumferential direction. For this reason, the floating caliper cannot extend out to the carrier arms in the circumferential direction and hence cannot be of the maximum possible width and rigidity.
Another spot-type disc brake of that same kind is known from the European patent No. 0,341,610. In that patent, the floating caliper is supported at a point in the center of the axially external brake shoe. For this purpose, the latter is formed with a radially outwardly pointing and preferably semicircular projection which engages a semicircular recess of the floating caliper. In contrast to the disc brake mentioned first, the floating caliper is not abutted against the lateral carrier elements of the brake shoe but extends past them in the circumferential direction . As a result, the width of the caliper is advantageously, widened to improve rigidity.
However, the lateral guide of the floating caliper at the semicircular projection of the brake shoe is less reliable. In certain mounting positions of the brake on the vehicle, for example, behind the wheel axle, the jolting received in this location may lead to the floating caliper being shifted laterally in the circumferential direction with respect to the brake disc on account of the play in its pin guide. In this case it will be urged into the radial direction and be jammed by the semicircular projection of the brake shoe.
The present invention has the object to avoid these disadvantages of the prior-art arrangements and to combine their advantages, that is to say, to create a spot-type disc brake whose floating caliper makes use of the maximum housing width and is safely guided in any mounting location.